natenate19

Right, so, taking a further look at this, it seems the following is the proper fix instead of simply commenting-out line 23 of:

wp-content/plugins/w3-total-cache/inc/functions/plugin.php

Thereby restoring partial functionality to W3 Total Cache, do this instead:

1)
Make sure the old fix is in-place:

https://www.itnota.com/fixing-php7-compatibility-issue-w3-total-cache/

2)
Update the following files:

wp-content/plugins/w3-total-cache/lib/W3/PgCache.php:    function ob_callback(&$buffer) {
wp-content/plugins/w3-total-cache/lib/W3/Plugin/NewRelic.php:    function ob_callback(&$buffer) {
wp-content/plugins/w3-total-cache/lib/W3/Plugin/Cdn.php:    function ob_callback(&$buffer) {
wp-content/plugins/w3-total-cache/lib/W3/Plugin/BrowserCache.php:    function ob_callback(&$buffer) {
wp-content/plugins/w3-total-cache/lib/W3/Plugin/Minify.php:    function ob_callback(&$buffer) {

Such that:

function ob_callback(&$buffer) {

becomes:

function ob_callback($buffer) {

If you’re paying attention, this is the exact same fix the original itnota.com fix applies, just extending it to everything else in the wp-content/plugins/w3-total-cache/lib/W3 directory and Plugin subdirectory. I have no idea why this is necessary specifically with PHP 7.0.9 and not with 7.0.8 and earlier PHP 7 minor versions, but it appears to be the case.

At any rate, once you’ve transposed everything in wp-content/plugins/w3-total-cache/lib/W3 and the Plugin subdirectory as noted above, and restarted php-fpm (etc.), W3 Total Cache appears to function as expected, persisting cache as expected as well.